100 degrees in a oven isn't going to cook the rat BUT I wouldn't use my oven LoL
Ziplock bag, sink full of hot water, couple plates to weigh down the bag and 30 to 40 minutes.
I do change out the water once or twice.
Then hair dryer to the head.
I don't feed f/t often because most of my snakes will only eat live so unless someone asks me to try and get one on f/t its a rare event.